Clutched power transmitting device with reduced lag time for actuation

Abstract

A power transmitting component can include a friction clutch, a ram, a pump, a fluid storage device and a valve. The ram can have a piston chamber and a piston movable therein between a first and second position to engage the friction clutch. A first inlet/outlet of the pump can be fluidly coupled to a reservoir. The fluid storage device can hold pressurized hydraulic fluid. The valve can be fluidly coupled with the piston chamber, a second inlet/outlet of the pump, and the fluid storage device. When in a first mode, the valve can permit fluid communication between the pump and the fluid storage device, inhibit fluid communication between the piston chamber and the pump, and inhibit fluid communication between the piston chamber and the fluid storage device. When in a second mode, the valve can permit fluid communication between the pump, the fluid storage device, and the piston chamber.

What is claimed is: 
     
       1. A power transmitting component comprising:
 a friction clutch having a plurality of first clutch plates and a plurality of second clutch plates that are interleaved with the first clutch plates; 
 a reservoir configured to hold a hydraulic fluid; 
 a hydraulic ram coupled to the friction clutch, the hydraulic ram having a piston chamber and a piston that is movable in the piston chamber between a first position which is retracted relative to the first and second clutch plates, and a second position in which the piston is extended toward the first and second clutch plates to a greater extent than when the piston is in the first position; 
 a pump having a first inlet/outlet and a second inlet/outlet, the second inlet/outlet being coupled for fluid communication with the piston chamber, the pump being operable in a forward mode wherein the pump is configured to pump fluid from the first inlet/outlet to the second inlet/outlet, and a reverse mode wherein the pump is configured to pump fluid from the second inlet/outlet to the first inlet/outlet; 
 a fluid storage device configured to hold a volume of pressurized hydraulic fluid; 
 a first valve element disposed between the fluid storage device and the piston chamber, the first valve element being configured to permit fluid communication from the fluid storage device to the piston chamber; 
 a second valve element disposed between the first inlet/outlet and the fluid storage device, the second valve element being configured to permit fluid communication from the first inlet/outlet to the fluid storage device and to inhibit fluid communication from the fluid storage device to the first inlet/outlet; and 
 a third valve element disposed between the first inlet/outlet and the reservoir, the third valve element being configured to permit fluid communication from the reservoir to the first inlet/outlet; 
 wherein the first, second, and third valve elements are configured to permit the pump to pump hydraulic fluid from the reservoir to the piston chamber when operated in the forward mode, and to permit the pump to pump hydraulic fluid from the piston chamber to the fluid storage device when operated in the reverse mode. 
 
     
     
       2. The power transmitting component of  claim 1 , further comprising a bleed conduit coupled for fluid communication with the piston chamber and the reservoir. 
     
     
       3. The power transmitting component of  claim 1 , further comprising a bleed conduit coupled for fluid communication with the fluid storage device and the reservoir. 
     
     
       4. The power transmitting component of  claim 1 , wherein the first, second, and third valve elements are elements of a first valve that is selectively operable in a first mode and a second mode, wherein the first valve permits fluid communication from the first inlet/outlet to the fluid storage device and inhibits fluid communication between the reservoir and the pump and between the fluid storage device and the piston chamber when in the first mode, wherein the first valve permits fluid communication between the reservoir and the first inlet/outlet and permits fluid communication between the fluid storage device and the piston chamber when in the second mode. 
     
     
       5. The power transmitting component of  claim 1 , wherein the fluid storage device includes a movable element, the movable element defining a second chamber and configured to apply pressure on hydraulic fluid within the second chamber, the second chamber being coupled for fluid communication with the first and second valve elements. 
     
     
       6. The power transmitting component of  claim 1 , wherein the first valve element is an element of a first valve, the first valve being selectively operable in a first mode and a second mode, wherein the first valve inhibits fluid communication from the fluid storage device to the piston chamber when in the first mode, and to permit fluid communication from the fluid storage device to the piston chamber when in the second mode.